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Acute effects of dynamic exercises on the relationship between the motor unit firing rate and the recruitment threshold.
- Source :
-
Human movement science [Hum Mov Sci] 2015 Apr; Vol. 40, pp. 24-37. Date of Electronic Publication: 2014 Dec 13. - Publication Year :
- 2015
-
Abstract
- The aim of this study was to compare the acute effects of concentric versus eccentric exercise on motor control strategies. Fifteen men performed six sets of 10 repetitions of maximal concentric exercises or eccentric isokinetic exercises with their dominant elbow flexors on separate experimental visits. Before and after the exercise, maximal strength testing and submaximal trapezoid isometric contractions (40% of the maximal force) were performed. Both exercise conditions caused significant strength loss in the elbow flexors, but the loss was greater following the eccentric exercise (t=2.401, P=.031). The surface electromyographic signals obtained from the submaximal trapezoid isometric contractions were decomposed into individual motor unit action potential trains. For each submaximal trapezoid isometric contraction, the relationship between the average motor unit firing rate and the recruitment threshold was examined using linear regression analysis. In contrast to the concentric exercise, which did not cause significant changes in the mean linear slope coefficient and y-intercept of the linear regression line, the eccentric exercise resulted in a lower mean linear slope and an increased mean y-intercept, thereby indicating that increasing the firing rates of low-threshold motor units may be more important than recruiting high-threshold motor units to compensate for eccentric exercise-induced strength loss.<br /> (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Subjects :
- Adult
Arm physiology
Elbow physiology
Electromyography
Humans
Isometric Contraction physiology
Linear Models
Male
Muscle Strength
Regression Analysis
Reproducibility of Results
Stress, Mechanical
Young Adult
Exercise physiology
Motor Neurons physiology
Muscle, Skeletal physiology
Recruitment, Neurophysiological
Subjects
Details
- Language :
- English
- ISSN :
- 1872-7646
- Volume :
- 40
- Database :
- MEDLINE
- Journal :
- Human movement science
- Publication Type :
- Academic Journal
- Accession number :
- 25514631
- Full Text :
- https://doi.org/10.1016/j.humov.2014.11.011